1. Field of the Invention
This invention relates to blade server systems and more particularly relates to a backplane of a blade server system.
2. Description of the Related Art
Blade computing is growing in popularity in the information technology (“IT”) realm. As more and more services are offered via computers and computer networks, the hardware to support these services grows in size and complexity. Data centers quickly fill with more and more servers as demand for services grow. This continual demand for more computing power results in more hardware. And as more and more hardware is added, management of the hardware, whether maintaining the networks, repairing damaged equipment, or other tasks, grows more and more complicated.
Blade servers offer an increasingly popular solution to the growing pains associated with other server systems. Blade servers are generally made up of thin blade modules (sometimes simply referred to as “blades”) that fit within a blade enclosure designed to provide support, power, and cooling to the blade server system. The core concept behind a blade server system is to remove from individual blade modules components that are unnecessary for the function that the particular blade is to perform. For example, a particular blade designed for processing may have a number of processors and sufficient memory to support the processing operations, but have all hard drive components removed, basic IO devices supporting peripherals such as keyboards removed, and power supply components removed. In contrast, a storage blade may have minimal processing capability but a great deal of storage. Removing items unrelated to the task the particular blade is to perform saves space, power, reduces heat, and decreases the number of components which may fail.
FIG. 1 shows one example of the basic structure of a blade server system. FIG. 1 shows a chassis 110 with backplane 120, a passage 116, a tray 112, and dividers 114. The chassis 110, also referred to as the enclosure, may provide a variety of services for the blade server system. For example, the chassis 110 may provide power for the blade server system and its constituent components. The chassis 110 may also provide cooling. The chassis 110 will typically have a tray 112 which, together with the dividers 114, separates the chassis 110 into blade module sized compartments. The user then inserts the individual blade modules into the compartments to integrate them into the system.
One component of a blade server system is a backplane 120, also referred to as a midplane. The blade modules typically plug into the backplane 120 which allows them to network and also provides power. In many embodiments, the backplane 120 is a passive component of the system in order to minimize the risk of a backplane failure.
However, the traditional backplane 120 has a number of failings. First, given the connectivity that the backplane 120 may need to provide, the backplane 120 is often a circuit board with considerable thickness. This makes manufacturing the board much more expensive and technically difficult to ensure that only the proper connections are made. In addition, the backplane 120 is generally a “one size fits all” solution for the blade server system; that is, a backplane 120 may be sized for a 3U system, a 20U system, or some other dimension. However, once the capacity of the backplane 120 is reached, the user must make an expensive upgrade to a new backplane 120. In other words, the traditional backplane 120 is not scalable.
The backplane 120 is generally designed to include only passive components since, if the backplane 120 fails, the entire blade server system is offline. Keeping the backplane 120 passive greatly reduces the risk of failure. However, active components may be useful in a backplane 120. For example, in a large system, signal buffers may be useful to strengthen signals that are travelling a long distance through the backplane 120. In addition, active components can provide valuable functions such as translating from one protocol to another (such as 10 GB Ethernet to Fibre Channel). Traditional blade server systems require a user to either forgo the benefits of these active components or force the user to incorporate them elsewhere in the system, which uses more space and complicates management. The backplane 120 simply is not a flexible solution. The backplane 120, once created, exists as it was created. The functionality or connectivity of the backplane 120 cannot be adjusted or tailored to the changing needs of the user.
In addition, the backplane 120 is a physical barrier to air flow through the chassis 110. Controlling the temperature in dense blade server systems is a significant challenge. Proper cooling of blade server systems and data centers is a field of expertise in and of itself. The barrier posed by the backplane 120 presents an obstacle since air needs to be circulated through the blade modules attached to the backplane 120. In many embodiments, the chassis 110 will house high-powered fans behind the backplane 120 which blow air through the passage 116 and thus circulate the air through the system. In short, cooling devices need to work around the backplane 120 as they cannot go through it. Even where holes are punched through the backplane 120, airflow is still restricted.